CHAPTER 136 Cervical Stenosis and Cervical Dilation
Cervical stenosis is a stricture or narrowing of the cervix. It is diagnosed by the inability to pass a 2-mm dilator into the uterus. Cervical stenosis can be either congenital or acquired. Acquired stenosis can result from postoperative scarring (from conization, whether it be cold knife, large loop electrosurgery, or laser; cautery; or cryotherapy of the cervix), cancer (endometrial or endocervical), radiation complications, infections, or atrophy from lack of estrogen (most common). In acquired cases the external os is most frequently affected (Fig. 136-1). In congenital cases, seen most often in nulliparous cervices, the stenosis is usually at the internal os.
Cervical Dilation
Treatment of cervical stenosis consists of dilation by using (1) progressive metal or plastic dilators, (2) osmotic tents, or (3) prostaglandin analogs. Laminaria tents are made from the stems of seaweed, usually Laminaria japonica, that is dried and made into sticks. Self-expanding cervical dilators (Dilateria, Lamicel) that resemble laminaria tents can also be used. Once the tents are placed into the endocervical canal, they rehydrate and expand, thereby causing dilation of the cervical canal (Figs. 136-2 and 136-3). Laminaria tents should not be used if pyometra is present or infection is suspected. The os and canal must be patent enough to admit the tents, which are available in several diameters. Some mechanical dilation may be necessary to allow their placement. Another option for the treatment of external os stenosis is the use of the carbon dioxide laser or a small radiofrequency loop excision. The latter two methods can remove a stricture that is readily visible externally.